1. Field of the Invention
The present invention relates to an assembly structure for a connector and, more particularly, relates to an assembly structure with two stacked connectors which is suitable used in 3 GHz˜6 GHz high frequency transmission.
2. Description of the Related Art
In general, the connector design at present, for concerning to reduce the positioned space on the motherboard, most connectors of the market use the stacked design to increase the plane elements capacity of the motherboard; For example, the U.S. Pat. No. 5,800,207 patent, which is relative to an assembly structure to a connector. But the connector structure of the U.S. Pat. No. 5,800,207 patent just stacks the connectors, it does not has a metal shielding shell molded as a whole, so it can not improve the whole shielding effect after stacking the connectors, namely, the electromagnetic interference (EMI) will be generated due to the noises between the two connectors can not be suitable eliminated, thus it will generate the bad influence to the transmission quality.
Additionally, the U.S. Pat. No. 5,037,330 patent discloses a shielded, stacked electrical connector assembly comprising an upper electrical connector and a lower electrical connector having respective insulating housings, wherein, the upper electrical connector and a lower electrical connector are stacked inside the insulating housings and then a metal shell is covered over the insulating housings, thus making the electrical connector assembly has certain ability of electromagnetic shielding effect; however, the conductive terminal of the aforesaid two connector must be soldered between the conductive surfaces of the printed circuit board, and for matching the requirement of the high frequency transmission, the transmission lines placed on the surfaces must has relative design corresponding to the high frequency characteristic (such as high frequency impedance match); however, it will generate mutually interference that it will further affects the transmission quality when the two connectors simultaneously transmit high frequency signal.
Additionally, the differential high frequency impedance design, its placement consists of one or more pairs of transmission signals (S+,S−), wherein, it further comprises a Signal ground and Chassis ground placed between pairs of transmission signals or other signals for separating, so as to prevent generating from interference and avoid other signals interfering the transmission signals (S+,S−). The distance between the transmission signals (S+,S−) is one of the key parameters that affects the high frequency impedance. Therefore, besides each transmission line has been insulated thus will increase the placement density, the line pitch, line width and line thickness between the two connectors and the controller must either be matched. Furthermore, the adjacent transmission lines of the two connectors also generates mutual inductance and mutual capacitor to form crosstalk interference phenomenon, and the phenomenon will be gotten seriously while the placement density of the printed circuit board being increased, especially, for long distance placement density of the printed circuit board (such as: BUS), thus will increase the difficultly for circuit designing.
Therefore, there needs an assembly structure with two stacked connectors which is suitable used in 3 GHz˜6 GHz high frequency transmission and overcomes the aforesaid drawbacks of the prior art.